Molding machine



l 1943- K. o. TOOKER 2,330,762

MOLDING MACHINE Filed June 6, 1941 4 Sheets-Sheet l fay! ' INVENTOR [fa/mall: 0. foo/{er BY 7 E @i TORNEY PL 1943. K. o. TOOKER 2,330,762

MOLDING MACHINE Filed June 6, 1941 4'Sheets-Sheet 2 I INVENTOR Kennel 0. 7001' ATTORNEY 4 Sheets-Sheet I5 K. O. TOQKER- MOLDING MACHINE Filed June 6, 1941 Sept; 28, 1943.

' Sept. 28, 1943. K b. TOOKER 2,330,762

MOLDING MACHINE Filed June 6, 1941 4 Sheets-Sheet 4 INVENTOR Kennel/z 0. Iaoker ATTORN EYS be cared for and cleaned. and expensive process of manufacturing belts has in the past restricted their speed of production- Patented Sept. 28, 1943 s Parana MOLDING MACHINE Kenneth 0. looker, Detroit, Mich, assignor to The Hoover Company, North Canton, Ohio, a

corporation of Ohio Application June 1941, sci-19.1 No. 396,799

. 13'Claims.

The present invention relates to molding ma.- chines and more particularly to improvements in the field oi molding rubber articles. More specifically the invention comprises a machine and a method by which rubber belts or similar articles may be made moresimply and with greater speed than heretofore. A

The molding of rubber articles is today a field of great importance and activity. Included in this field are rubber belts which are useful in many connections and particularly for the purpose of power-transmission. These belts may be made in various sizes and shapes but are usually circular, round or elliptical in cross-section.

They find a particular use in suction cleaners in which power is transmitted from the driving motor shaft to a rotating agitator positioned within the cleaner nozzle.

Heretofore it has been the practice in making rubber belts and similar articles to mold these items sin y. that is, one to a cavity. A plurality of mold cavities might be synchronously operated but only a single belt would be formed in each cavity. Possibly as many as twelve or thirteen individual mold'cavities can be operated ina single molding press but the number is limited by the platen area required for the side-by-side arrangement of the cavities. Belts made in this manner have individual fiashings which represent a waste of rubber and which must be removed from the belts before they can be sold and placed into operation. Also the operating of the molding machine itself is relatively expensive as there are a multiplicity of individual cavities to This relatively slow and held their selling price at an unduly high 7 level. In the molding machine of the present invention the disadvantages which have characterized the former machines and methods have been sub- Figure V8 is a showing of the mold partly closed stantially eliminated. Aplurality of belts are formed and made in a single mold and, as there may be substantially as many'molds operated by y each molding press as in the former methods, the

of the speed of operation and making can be i sold for a lesser price.

It is' an object of the invention to provide a rubber belt-molding machine in which a single charge of rubber compound is formed into a plurality of adjacent circular belts by the use of a single force plug from which the belts are stripped upon the opening of the mold. A still further object of the invention is to provide a mold for rubber articles in which a two part outer mold element is laterally separable and a force plug moves longitudinally relative thereto. the

outer mold element being formed to retain the product and to strip it fromthe force plug in the opening of the mold. A still further object of the invention is to provide a molding machine in which a plurality of molds each forms a cluster of belts. These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawings to which they relate.

Referring now to the drawings in which a preferred embodiment of the present invention is disclosed, and in which the same reference character refers to the same parts in the various views:

Figure l is a vertical cross section through a single mold positioned in a rubbe molding press;

Figure 2 is an isometric view, partly in section, whichshows .the separable outermold element movably positioned in thelower steam plate in the open position;

Figure 3 is an isometric view of a segment of the mold and illustrates a retention recess and stud provided to receive excess rubber from the mold proper the purpose of which is to form such rubber into retaining means for the belt cluster when the. force plug is separated Figure 4 is a section upon the line H of Figure 3 and illustrates the manner in which the surplus rubber encloses the retaining stud;

Figure 5 illustrates the first step in the process of forming a new belt cluster). with the rubber compound positioned in the mold and the force plug ready to advance therein:

and illustrates the manner in which the charge is forced upwardly between the force plug and the two piece outer mold member;

Figure 7 illustrates the first step in the opening of the mold, the steam plate supporting the outer steam plate and the force plug is displaced thereirom, the belt cluster starting to strip from the force plug under the retaining action of the button-like studs;

Figure 9 is a view of the final step with the press completely opened and the force plug with-.

drawn entirely from the mold, the belt cluster being turned inside out and removed entirely iron: the force plug;

belts as taken from the mold without being turned inside out;

Figure 11 is a view in perspective of a single belt made in accordance with this invention;

Figure 12 illustrates the method of separating ing press is indicated but it is to be understood 7 that a plurality of such units comprise the entire press, and that the unit disclosed is illustrative of each of the individual units. In the drawings the reference character I indicates the platen which supports a plurality of the molding units which are constructed as hereinafter described.

Platen I is an enlarged fiat topped table which is supported by an hydraulic lifting mechanism of any suitable type the vertical plunger 2 of which is seen to be positioned immediately thereunder.

A pluralltyof vertical guide posts 8 direct the.

platen I in its vertical movement toward and from the, top platform or platen 4 which carries,

as will be hereinafter set forth, a part of the mold which cooperates with the mold element carried by the platen I.

I A steam plate 6, formed with steam-conduct ing passageways l, is carried by platen I by the spaced vcrtically extending side arms 8 of the support 9, the latter being secured to the top of the platen I by a tongue and groove relationship illustrated at II. The steam plate 6 is formed with an upwardly facing recessed mold seat inforce plug 26 is a fixed element in each instance.

Figure 10 is a view of the finished cluster of provided with identical semi-circular channels, here indicated by 26, which in each instance are adapted to oppose and cooperate with one of the channels in the outer mold member to form a circular passageway which is also circular in cross section. The plug flts within the mold section I6 and other than at the aforementioned channels and at the rim-like recess I9 there is but very. slight clearance, about inch, between the plug and the outer mold memberat any point. Being carried by the upper steam plate 24, which is itself carried by the fixed upper platen 4, the

To insure that the plug will at all times be in exact alignment with the cylindrical recess cooperating outer mold member, which is mounted for vertical displacement with the steam plate 6, there are provided a plurality of vertically extending guide posts 3| which extend downwardly from the upper steam plate and passslidingly through vertical bores 32 in the lower steam plate '6.

While it is clear that the vertical displacement of the lower steam plate 6 together with the mold sections I6 will move the outer mold sections I6 from the upper force plug 26, it is also clear that if the mold cavities are filled with l solid material that such displacement without shearing will not be possible. Accordingly, it becomes necessary that the outer mold be opened in the sense of expanded or outwardly withdrawn before such displacement takes place. To permit 1 of lateral movement of the mold sections I6 there dicated at I2. the bottom and side walls of which I extend horizontally and vertically, respectively,

while the end walls thereof are inclined, asindi cated at I3, to form diverging guide surfaces for a purpose which will be hereinafter disclosed.

sections of which are indicated by the reference character I6, is positioned within 'the mold seat 40 A two piece outer mold member, the parts or I2 and is formed with exterior surfaces which exactly conform to the bottom and side walls of the mold seat so that it is adapted to fit snugly therein. Sections I6 make contact along a dividing vertical plane and in their-closed position form a cylindrical recess the sides of which are corrugated by a plurality of circumferential channels each of which is semi-circular in cross section, as indicated at I1, and which are separated by extremely small distances. A flat bottom surface I6 is spaced somewhat from the lowermost channel I! and the uppermost channel is spaced somewhat below the top of the mold member. Each mold section is formed with a shallow rim-like recess I6 surrounding the top of the main cylindrical recess for the purposeof receiving the overflow of surplus material which is known-as the flash. Atspaced intervals circumferentially of thi rim-like recess I9 .are deeperrecesses 2| upwardly within each of which projects a button-like stud 22 formed with an overhanging lip portion at its upper edge. Recesses 2| are adapted to be filled by the overflow rubber or flash to form retaining means which at a later stage in the operation of the press will function to hold, at least temporarily, the molded objects to the outer mold member.

An upper steam plate 24, provided with steam passageways 25, carries a cylindrical force plug 26 and isfixedly secured, as by means of bolts 21, to the upper platen 4. Force plug 26 is adapted to fit'between the mold sections I6 and is is provided on each side of each section an inclined guideway 34 which extends parallel to the sloping end walls I3, it of the steam plate 6. Within each channel 34 is positioned a pair of supporting rollers 36 each of which is carried upon a stud 31 fixedly carried in the adjacent wall of the steam plate. The relationship is such that if the steam plate 6 is moved downwardly and the mold sections l6 are held in place, the mold sections I6 are moved, apart transversely and, in effect, slide along the outer sloping end walls I3 of the steam plate although in fact they are guided and carried by the rollers 36. This is exactly the operation which takes place in the expansion of the outer mold member. To limit the vertical movementbetween the mold sections I6 and the steam plate 6 there are provided a plurality of stops 39 which are secured to the upper face of the steam plate 6 by screws 4i and so arranged as to abut vertical shoulders 42 at the outer comers of the mold sections I6 in the uppermost positions of the sections relative to the plate.

In order to obtain the expanding or spreading action of the mold sections I6 which will enable the force plug 26 to be-withdrawn after the molding operation is completed, there v is provided means which will hold sections I6 against downward vertical movement with the steam plate 6 during the initial'one and one-half inches of movement of the plate which will enable the the cylinder head. A second plunger 52 seats.

upon the top of plunger 66 and extends slidingly through a bore 63 in the steamtable 6, being pro-" vided with an enlarged flat topped head 66 which positioned within a sump 65 in the bottom face of the mold seat I2 in the steam table 6. A fluid conduit 61 connects to the lower end of the cylinder t6 and is adapted to convey fluid under "formed any excess material will flowand escape pressure thereto which will drive the piston 66 upwardly within the cylinder.

The structure necessary to mold one cluster of exception. One or more let openings 65 are positioned in the side wall ofplate 6 so that itj faces the space between the outer'mold sections it in the open relationship. A lubricant passes.

through the jet under the. force ofa carrying stream of air from a pipe "which aspirates the lubricating material from the feed line pipe 61.

As will be explained this lubrication assists in I the removal of the belt cluster from the mold.

It is to be understood that it is exemplary and that a plurality of such units are adapted to be actuated in the same press, that is, a plurality of belt clusters can be molded by similar molds positioned between the lower movable platen I and the upper stationary platen 6 of the press' "10 belts has now been described with but a slight between the abutting top surfaces.

With the force plug "advanced into the mold for its full length the space between the parts 'isindicatedlby the product shownin isometric viewin Figure 10. The cooperating channels I! in the outer mold sections I6, and 26 in the force plug 26, have formed a stack of circular rubber belts II which may be referred to .as a cluster, one of the belts of which is illustrated in Figure 11. a The belts of the cluster are inter- At the inner or lower end a flash 62 is formed beconnectedbynarrow thin webs or flashes.

twee'nthe bottomof the forceplug and the bottomwall I6 of the mold sections I6 whileat the "outer or upper end a rim-like flashing 66 is j formed from which'extenda. plurality .of'hollow .protuberancesfl bf the exact size and shape of 3 cluster as illustrated in Figure 10 is inverted, that is, the flash 63 is at the The operation of the device constructed in accordance with the invention will now be disclosed and is as follows, reference being made particularly to Figures Ste 9 of the. drawings; A cylindrical block 56 of the rubber compound formed of the desired ingredients is placed upon the bottom face I6 of the closed outer mold memher, the sections I6 of which are in abutment as illustrated in Figure 5. The lower mold memthespace between the recesses 2| and the button-like plugs 22 therein. In the mold the belt top while the flash 62 is at the bottom. e

After the mold parts have been in a closed relationship for some ten minutes at a temperature of approximately 302 degrees Fahrenheit the rubber belt cluster is sufliciently cured and the mold iis ready to be opened.

The first step in the operation of opening the mold is illustrated in Figure '7. The lower platen I begins its downward movement and carries with it the steam plate 6 and the cylinder or casing 66 of the auxiliary hydraulic lifting mechaher is spaced downwardly from the upper force plug 26 but steam passes through the upper and lower plates and the mold and the force plug are at high molding temperatures.

In the first step of the operationthe 10" er wise the upward movement of the lower platen l is guided by the vertical guides 6. The force plug 26 enters the recess formed by the mold sections it as illustrated in Figure 6 and makes contact with the block ofcompound indicated at 66. Immediately that' material is placed under pressure and is forced transversely and travels upwardly between the force plug and the mold nism. Fluid under pressure is admitted into the cylinder 66 through the conduit 61 in the auxiliary lift and a pressure is exerted upon the piston 66 which forces itupwardly and so exerts a pres- ,sure through the plungers 46 and 62 upon the flat toppedhead 660i the upper plunger. This latter element abuts the flat bottom face of both of the outer mold sections I6 and forces them against the bottom face of the steam plate 26 which carries the force plug 26. The result is that as the steam plate 6 moves downwardly the a piston 66 moves upwardly under the pressure exerted thereon and holdsthe mold sections I6, I6 in place. As the steam plate 6 moves downward- 1y relative to the mold section I6, however, the supporting rollers 36 move downwardly in their channels 66 and, inan obvious manner, force the sections I6, I6 apart. This relative movement between the mold sections I6 and the steam plate 6 continues for approximately one and onesections 96 as illustrated in Figure 6. This flow of the material continues until the force plug has extended its full length into the outer mold and the lower flat face of the steam table 26has abutted top face of the mold sections I6 at which time the only escape for the overflow rubber is between the abutting faces in the rim recess I6.

half'inches of plate travel at the end of which the mold sections I6 have advanced until their abutment shoulders 62' have contacted the stops 26. This relationship is illustrated in Figure 7 and his clear that in such relationship the recesses II are spaced entirely from the belt cluster which encloses and'is carried by the force plug 26. I I 1n the third step of the opening operation, as

Through this and into this rim recess flows all the excess rubber to form a flash; the-rim.

leading ely to the recesses 2I' is some- L- what deeper, a large part of the-overflow rubber flows into those pockets and about the retainillustrated in Figure 8, the outer mold section I6 moves downwardly with the steam plate 6. The

upper flash 63 is held in place by its interlocking relationship with the button-like studs 22 and the belt cluster begins its stripping movelng studs 22. The amount of rubber compound 66 which was placed into the mold was predetermined so as to fill all of the cavities with but very little overflow but, as is well known, any

excess material willf'orce its way between metallic parts even though they are in close con-y tact. Accordingly, after the product has been ment from the force plug 26. Actually the upper flash rim 66 draws the upper belt of the cluster down and over the lower belt and reverse:

the entire cluster inside out. To facilitate this inversion and to reduce the friction of the sliding contact there areprovided, as described, one

-or more lubricating jets 66 through which'air under pressure from a feed line 6 6 exhausts a lifted by an atomizing action .through a feed line 61. The jet opening 85 is so positioned and directed as to spray upon the surface of the belt cluster so that in the reversal and turning movement the belt cluster will slide upon itself with a minimum of friction thereby preventing tearing.

4 In the final step 01' the action the force plug 26 is withdrawn entirely from the belt cluster which'has been turned inside out, as illustrated in Figure 9. The cluster continues to be carried by the lower-outer mold member through the retention action of the rim 83 with the button-like plugs 22. From this position it is readily displaced manually by an operator, however, who will lift one corner of the rim and detach it from the plug.

It is believed to be clear that a plurality of such units can be made in a single press in accordance with the method which has just been described in connection with the formation oi?v a single belt cluster, it being necessary only that the mechanism which has been described for a single unit be mounted between the upper and lower platens I and 4 of the same press.

Upon the belt cluster being removed from the I mold it is desirable that the cluster be'separated 2 into individual belts and the end flashes cut away. This is accomplished by sliding the jaws of an expansible mandrel 68 into the cluster and arranged that with said platens in close proximity'said projection element extends into.

lubricating fluid, such as glycerine and water,.

There is also saving of time in the preparation of the initial charge for only one large charge is necessary for a plurality of belts rather than individual charges for each belt. There are numerous other advantages which accrue from the present invention but from the foregoing it is believed that it is apparent that the advantages which are gained are extremely important.

I claim:

1. A molding machine including two relatively movable supporting platens, cooperating interfitting mold elements carried by said platens for. movement toward and from each other, one of said elements being recessed and the opposing element upon the opposite plate having a projection, said mold elements being so constructed said recessed element, said recessed element beand then expanding the jaws, as illustrated clearly in Figure 12. The outer surfaces of the jaws are made to conform to the contours of the belts and the cluster is securely fixed in place. The mandrel 68 is then rotated in contact with a gang cutter comprising a plurality of blades 39 lng expansi-ble laterally of the direction oi move- -ment or said elements toward and from each other, means to vary the distance separating said'platens and so said mold elements, and means togexpand said recessed mold element laterally of the direction of movement of said platens during the initial separating movement 1 thereof and prior to separation 01 said projection element from said recessed element.

' element upon the opposite plate having a projection, said elements'being so constructed and arranged that with said platens in close proximity said projection element extends into said recessed element, said recessed element being 7 formed of a plurality of parts displaceable laterally relative to the direction of movement of said 1 mold elements toward and from each other, and

jaws l0 permits the belts to be removed axially flash appears at the side of the belt whereas in belts constructed heretofore the flashing apmeans movable with the platen carrying said recessed element to displace said parts laterally during an initial opening movement of said lastmentioned platen and prior to separation of said.

' projection element from said recessed element.

3. In a 'molding machine, a first platen, a

second platen, means to move said second platen toward and from said first platen, a force plug carried by said first platen, an outer mold member comprising a plurality of individually movpears upon the inside and upon the outside a saving in the time of the operator for he needs but to place a single charge to make nine belts where heretofore it has been necessary for him to place charges in nine molds. Likewise time is saved in the cleaning of the molds.

ation to remove the flashes for nine belts can be trimmed in a single operation whereas heretofore the belts of necessity were trimmed singly. One very important improvement and saving lies in the fact that with a given platen area in a press a greater number of belts can be produced than by conventional production methods.

able parts, means mounting said outer mold member on said second platen for synchronous longitudinal and lateral movement of the individually movable parts thereof relative to said second platen, means to hold said outer mold There is additional saving of time in the trimming opermember carried by said second platen against longitudinal displacement of said mold during the initial longitudinal displacement of said second platen from said first platen, and means to eflect the lateral movement of said individually movable parts of said outer. mold'member'during said initial longitudinal displacement of said second platen.

4. In a molding machinaa first platen, aseconcl of said outer mold member upon the movement of said second platen and means to hold said outer mold member against displacement relative to said force plug during an initial movement with said one platen during the initial. movement thereof from said second platen and,

ment of said second platen from said first platen.

whereby said guide means eiiect an opening of said outer mold member, said last mentioned. holding means comprising an auxiliary hydraulic lift of restricted displacement movable with said second platen.

5. In a molding machine, a first steam plate, a force plug carried thereby, a second steam plate,

an outer mold member carried by saidrsecond upon separation of said steam plates, said re- I including an auxiliary hydraulic lift.

9. In a belt-molding machine, a divided outer mold element adapted to receive the 'moldable material, formed interiorly with a plurality o! circular grooves,.and with a. flash-receiving seat shaped to form a locking flashing, a cylindrical force plug formed on. its, exterior with a plurality of circular grooves adapted to mate with the grooves in said outer mold element to form the molded belt, means to expand said divided mold taming plugs functioning to retain a molded 5 product on said outer mold member and to draw it from said force plug.

6. In a molding machine, a first steam plate, a force plug carried thereby, a second steam plate, an. outer mold member carried by said second steam plate comprising a plurality of individual parts shaped to form in the assembled condition a recess for said force plug, an overflow channel atv the side of said outer mold member including means. to receive overflow from the mold and to retain it against a tension exerted by the force plug on the molded article, means to move the steam plates and so the force plug and the outer mold member toward and from each other, and means connected to one of said steam plates to spread the individual parts of said outer mold member prior to movement thereof with said second steam plate.

7. A molding machine including two workmolded article, and means to move said movable element laterally outwardly of said force plug I to move said flash receiving seat away irom. said force plug to separate the molded belt from said "force plug, and means to separate said expanded divided mold element and said force plug longitudinally of each other.

10. In a molding machine, a first mold element formed of movable parts, a second. mold element cooperating with said first moldelement to tom the article tobe molded, a flash receiving seat on said movable parts to receive the flash of the parts laterally of said second mold element, said flash receiving seat moving with said laterally moving parts to exert a force on the molded flash.

- to separate the molded article iromsaid second carrying platens, a mold element carried by each of said platens arranged and constructed for nesting in certain relative positions of said platens, means for moving one or said platens to-.-

ward and from the second platen, the mold element carried by said one platen comprising a plurality of individually movable parts, and

the direction 0! movement of said one platen during the initial movement of said one platen of said platens arranged and constructed ior nesting in certain relative positions of said platens, means for moving one of said platens toward and from the second platen, the mold element carried by said one platen comprising a plurality of individually movable parts, and means to move said parts laterally relative to'the direction oi movement of said one platen during the initial movement of said one platen from said second platen including means mounting the individually movable parts of the mold element on said one platen for lateral displacement upon being moved relative to said one platen in the direction 01' movement of said platen, and also means to hold said individually movable parts against movemold. element. I

11. In a molding machine, a first mold element formed of movable parts, a second mold element cooperating with said first mold element to form the article to be molded, a flash receiving seat on said movable parts to receive the flash of the molded article, means to move said parts laterally oi said second mold element, said flash receiving seat moving with said laterally moving parts to exert a force on the molded flash to separate the molded article from said second mold element, and means to separatev said'mold elements longitudinally of each other after said lateral movement of said parts to completely remove sald second mold element irom the molded article.

12. In a molding machine, a first mold element" formed of movable parts, a second mold element cooperating with said first mold element to form means to move said parts laterally relative tothe article to be molded, a flash receiving seat on said parts to rceive the flash of the molded article, and cooperating cam means to move said- 7 parts laterally of said second mold element to separate the molded article from said parts. said flash receiving seatmoving with said laterally moving parts to exert a force on the molded flashmold element. a

13. In a molding machine, a first mold element formed of movable parts, a second mold element cooperating with said first mold element to form the articleto be molded, a flash receiving seat on said parts to receive the flash oi the molded article, means to move said parts laterally oi said second mold element to separate the molded article from said parts, said flash receiving seat" moving with said laterally moving parts to exert a force on the molded flash to separate the molded article from said second mold element, means to separate said mold elements longitudinally of each other after said lateral movement of said parts to completely remove said second mold element from the molded article, and means to inject a lubricant upon the molded article during said longitudinal separation.

O. TOOKER. 

